The invention relates to a device for manual replacement of a roller of a copying machine and more particularly to a device for manual replacement of a copying machine fuser roller.
Copying machines are known in the form of copiers in which a roller is replaceable for service purposes, the roller being equipped with a carrying feature, in which it can turn freely around its center axis. The copying machine has rollers, in a roller pair arrangement, for routing and delivering a toner image-bearing recording medium in the form of a sheet or strip. The rollers are supported at their axial ends and are operated in rotation in an adjoining, axially parallel arrangement in bearing points of the copying machine. There are manually activated mechanisms for releasing the rollers in their bearing points, and for separating the rollers in the radial direction for purposes of removing them from, and inserting them into, their bearing points.
U.S. Pat. No. 4,121,089 discloses a copier machine, in which the fixing unit for toner image-bearing sheets of paper can be removed laterally from the copier for service purposes and has a mechanism in the form of a manually actuated swiveling lever system for release of the fixer/heating roller. The fixing/heating roller moreover has carrying features, for its replacement and carrying. The carrying feature is in the form of a single U-shaped carrying handle which is located rigidly on a U-shaped holding frame spaced in the middle between the axial ends of the fixing/heating roller and radially to the center axis of the roller. The U-shaped holding frame, on its free U-leg ends, has one pivot bearing each for one of the axial shaft ends of the roller in which it can be freely turned. Moreover, the holding frame, on the outside, on its free U-leg ends, has cube-shaped, separate bearing blocks which are connected rigidly to the leg ends. The fixing/heating roller can be inserted/removed into/from the U-shaped bearing points of the fixing unit by the cube-shaped separate bearing blocks. The pressure roller, which is located obliquely underneath the fixing/heating roller, does not have any carrying handles and can only be replaced using a tool.
The deficiency of this disclosed prior art arrangement is that when using large, heavy rollers, for purposes of improving fixing quality, it is difficult to replace and carry the fixing/heating roller by a single central carrying handle without jamming and damaging of the bearing points. Removing a heavy, hot fixing/heating roller and depositing it on a resting surface cannot be done without endangering the service personnel and damaging the roller, since when the roller is laid down it lies directly on the resting surface and can roll away. Furthermore, due to the alignment of the input/output openings of the machine-side U-shaped bearing points, which alignment deviates from the vertical, it is very difficult to insert a large, heavy roller using the central carrying handle, since the roller must be swiveled around the carrying handle to be inserted into the bearing points. Moreover, for purposes of replacing the pressure roller the disclosed embodiment and arrangement of the carrying handle could not be used since the carrying handle would project into an area of the transport path for the toner image-bearing sheets.
Therefore it is an important purpose of the invention to provide a device which overcomes these defects, and which makes it safer and easier to carry out customer service of the copying machine, especially the replacement of heavy and large rollers, and moreover has a simple, compact, economical structure.
The purpose of the invention is achieved with a device wherein rollers have on their two axial ends one carrying handle each, as the carrying mechanism, which handles are located eccentrically to the center axis of the roller. Accordingly the roller hangs down vertically underneath the carrying handles due to its weight in the manual removal from and insertion into the vertically and radially oriented input/output openings of the bearing points of the copying machine. Advantageously, the carrying handles are attached using annular mechanisms to annular pivot bearings which are concentrically located rigidly on the shaft ends of the roller, and the carrying handles of the roller project in the axial direction beyond their bearing points in the machine. Furthermore, the two attachment mechanisms of the carrying handles are axially and radially centered, guiding and holding of the roller in its machine bearing points; and the two attachment mechanisms of the carrying handles aid in depositing the roller which has been removed from the bearing points on the machine on a resting surface.
Advantageously the carrying handles are attached using annular means to annular pivot bearings which are concentrically located rigidly on the shaft ends of the roller, and the carrying handles of the roller project in the axial direction beyond their bearing points in the machine.
Furthermore, the two attachment means of the carrying handles have means for axial and radial centering, guiding and holding of the roller in its machine bearing points; and the two attachment means of the carrying handles have means for depositing the roller which has been removed from the bearing points on the machine on a resting surface.
Moreover the mechanism for centering, guiding and holding the roller are essentially annular disks which are located concentrically around the shaft ends of the roller. The outside diameter of the disks is greater than that of the roller; and the means for depositing the roller are made as a flattened area on the outside periphery of the annular disk of the means on the bottom side opposite the carrying handles, the flattened area with its support surface projecting by a predetermined amount beyond the outside diameter of the roller.